Among the conventionally-known front vehicle body structures are ones where a front sub frame disposed under and fixedly connected to left and right side frames and front suspensions are attached to left and right end portions of the front sub frame. In such front vehicle body structures, a power source (engine) is disposed forwardly of the front sub frame, and the power source is connected, via a support member, to a substantial middle region of the front sub frame so that the power source is supported by the front sub frame (see, for example, Japanese Patent Application Laid-Open Publication No. 2000-238656). According to the front vehicle body structure disclosed in the 2000-238656 publication, when front wheels are braked during travel of the vehicle, loads are applied, in a width direction of the vehicle body, from the front suspensions to the front sub frame. Further, in order to bear the loads applied from the front suspensions and support the power source, a cross member is attached to the front sub frame to secure a sufficient rigidity of the front sub frame.
Further, in some of the conventionally-known front vehicle body structures, a steering gear box is mounted to the front sub frame by means of a combination of fastening bands and fixing bushes, or only by means of a plurality of fixing bushes.
With the conventionally-known front vehicle body structures, loads applied from the front suspensions to steering tie rods due to braking of left and right front wheels can be borne by steering-gear-box mounting members, such as the fixing bushes. However, because a steering gear pinion and electric assisting motor are provided on an end portion of one of left and right sides of the steering gear box, it is difficult to position the mounting members, such as the fixing bushes, in left-right symmetrical relation to one another. Thus, the left and right tie rods tend to move different amounts when loads are applied from the front suspensions to the steering tie rods. Therefore, it has been considered difficult to achieve same toe angle changes between left and right wheels caused by braking loads.
Further, with the front vehicle body structure disclosed in the 2000-238656 publication, it is necessary to provide a cross member on the front sub frame in order for the front sub frame to have a sufficient rigidity for bearing loads applied from the front suspensions and supporting the power source. The provision of the cross member on the front sub frame undesirably increases the number of necessary component parts, which would impede enhancement of productivity.